System for conducting high-temperture thermolysis of waste mixture

Abstract

A system for conducting high-temperature thermolysis of a waste mixture formed by sewage sludge and wood waste (e.g., creosote-impregnated wooden railway sleepers and utility poles) is proposed. The products of the high-temperature thermolysis may be used to produce thermal energy, electrical energy, carbon black, and liquid fractions which may be used profitably for various purposes.

1 . A system for conducting high-temperature thermolysis of a waste mixture, comprising:
 a sewage sludge storage configured to receive and store sewage sludge;   a wood waste storage configured to receive and store wood waste;   a grinding unit coupled to the wood waste storage and configured to grind the wood waste;   a mixer configured to form the waste mixture by mixing the sewage sludge from the sewage sludge storage and the grinded wood waste from the grinding unit;   a screw-conveyor dryer configured to heat and dehumidify the waste mixture;   a metering hopper arranged between the mixer and the screw-conveyor dryer, the metering hopper being configured to perform a metered supply of the waste mixture from the mixer to the screw-conveyor dryer while replacing ambient air with carbon dioxide (CO 2 );   a striker mill coupled to the screw-conveyor dryer ( 9 ) and configured to conduct the high-temperature thermolysis of the waste mixture and regrind the waste mixture;   a cyclonic separator coupled to the striker mill and configured to separate the waste mixture subjected to the high-temperature thermolysis and regrinding into a solid fraction and a gaseous fraction, the solid fraction of the waste mixture comprising carbon black;   a carbon black storage coupled to the cyclonic separator and configured to receive and store the carbon black;   a refrigerator-type condenser coupled to the cyclonic separator and configured to obtain a thermolysis liquid and a synthesis gas by cooling and condensing the gaseous fraction of the waste mixture;   a first thermolysis liquid storage coupled to the refrigerator-type condenser and configured to receive and store the thermolysis liquid;   a first synthesis gas storage coupled to the refrigerator-type condenser and configured to receive and store the synthesis gas;   a second synthesis gas storage coupled to the first synthesis gas storage;   a gas compressor arranged between the first synthesis gas storage and the second synthesis gas storage, the gas compressor being configured to pump over the synthesis gas from the first synthesis gas storage to the second synthesis gas storage while increasing a pressure of the synthesis gas up to 12 atm;   a second thermolysis liquid storage coupled to the gas compressor and configured to collect and store a secondary thermolysis liquid resulted from compressing the synthesis gas by the gas compressor when pumping over the synthesis gas from the first synthesis gas storage to the second synthesis gas storage;   a fine gas filter coupled to the second synthesis gas storage and configured to clean the synthesis gas from mechanical impurities;   a gas holder coupled to the fine gas filter and configured to receive and store the synthesis gas under pressure of up to 30 atm; and   an energy conversion unit coupled to the gas holder and configured to convert chemical energy stored in the pressurized synthesis gas into thermal energy and electrical energy.   
     
     
         2 . The system of  claim 1 , wherein the grinding unit comprises:
 a first grinding subunit configured to grind the wood waste to coarse wood-waste fractions ranging in size from 100 mm to 200 mm;   a second grinding subunit configured to grind the coarse wood-waste fractions to medium wood-waste fractions up to 30 mm in size; and   a third grinding subunit configured to grind the medium wood-waste fractions to fine wood-waste fractions up to 6 mm in size.   
     
     
         3 . The system of  claim 1 , wherein the sewage sludge has a humidity of 18% and a fragment size of 2-6 mm. 
     
     
         4 . The system of  claim 1 , wherein the sewage sludge storage is equipped with a moving floor. 
     
     
         5 . The system of  claim 1 , further comprising:
 a sewage sludge silo arranged between the sewage sludge storage and the mixer;   a wood waste silo arranged between the grinding unit and the mixer; and   a waste mixture silo arranged between the mixer and the metering hopper;   wherein each of the sewage sludge silo, the wood waste silo and the waste mixture silo is configured as a cylindrical top-loaded reservoir comprising a charging bucket conveyor and a discharge screw conveyor.   
     
     
         6 . The system of  claim 1 , wherein the metering hopper comprises:
 a screw conveyor having a first end and a second end;   an electric drive coupled to the first end of the screw conveyor, the electric drive being configured to drive the screw conveyor;   a working chamber coupled to the second end of the screw conveyor;   a charging cone attached to the screw conveyor near the first end of the screw conveyor;   an air outlet nozzle attached to the working chamber;   a carbon dioxide inlet nozzle attached to the screw conveyor near the first end of the screw conveyor; and   an electric sliding gate attached to the working chamber from below, the electric sliding gate being configured to cause the waste mixture to move from the working chamber to the screw-conveyor dryer.   
     
     
         7 . The system of  claim 1 , wherein the screw-conveyor dryer comprises:
 a hollow body comprising an inlet nozzle, a top coupling pipe, an outlet nozzle, a bottom tube, a bottom coupling pipe, a middle tube, and a top tube, wherein each of the bottom tube, the middle tube and the top tube having a screw conveyor arranged therein, the inlet nozzle is coupled to a system for supplying a gaseous heat-conducting medium to the hollow body, the outlet nozzle is coupled to a system for removing the gaseous heat-conducting medium from the hollow body, the top coupling pipe is configured to connect the top tube and the middle tube, the bottom coupling pipe is configured to connect the middle tube and the bottom tube, and the middle tube is larger than the top tube in diameter but smaller than the bottom tube in diameter;   a top electric drive coupled to the screw conveyor in the top tube;   a middle electric drive coupled to the screw conveyor in the middle tube;   a bottom electric drive coupled to the screw conveyor in the bottom tube; and   a charging hopper attached to the top tube and configured to receive the waste mixture from the metering hopper.   
     
     
         8 . The system of  claim 1 , wherein the striker mill comprises:
 a working chamber having a first cavity and a second cavity, the first cavity having a cylindrical part and a toroidal part, the cylindrical part having a bottom, the cylindrical part and the toroidal part being interconnected near the bottom of the cylindrical part through an annular slot, the cylindrical part having an inlet pipe coupled to the screw-conveyor dryer and an outlet pipe coupled to the cyclonic separator, the second cavity surrounding the toroidal part of the first cavity, the second cavity having at least one inlet nozzle for a heat-conducting medium and at least one outlet nozzle for the heat-conducting medium;   a vertical drive shaft having a first end arranged outside the working chamber and a second end arranged inside the cylindrical part of the first cavity;   an electric drive coupled to the first end of the vertical drive shaft; and   a horizontal spreading disk attached to the second end of the vertical drive shaft, the horizontal spreading disk being arranged opposite to and aligned with the annular slot, the horizontal spreading disk being configured to feed the waste mixture into the toroidal part of the first cavity through an upper section of the annular slot and to remove the waste mixture subjected to the high-temperature thermolysis and regrinding from the toroidal part of the first cavity through a lower section of the annular slot.